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arXiv · 2510.17286

Trapped-ion two-qubit gates with >99.99% fidelity without ground-state cooling

A. C. Hughes·R. Srinivas·C. M. Löschnauer·H. M. Knaack·R. Matt·C. J. Ballance·M. Malinowski·T. P. Harty·R. T. Sutherland
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Abstract

We introduce the 'smooth gate', an entangling method for trapped-ion qubits where residual spin-motion entanglement errors are adiabatically eliminated by ramping the gate detuning. We demonstrate electronically controlled two-qubit gates with an estimated error of $8.4(7)\times10^{-5}$ without ground-state cooling. We further show that the error remains $\lesssim 5\times10^{-4}$ for ions with average phonon occupation up to $\bar{n}=9.4(3)$ on the gate mode. These results indicate that trapped-ion quantum computation can achieve high fidelity at temperatures above the Doppler limit, which enables faster and simpler device operation.

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A. C. Hughes, R. Srinivas, C. M. Löschnauer, H. M. Knaack, R. Matt, C. J. Ballance, M. Malinowski, T. P. Harty, R. T. Sutherland. 2025-10-20. Trapped-ion two-qubit gates with >99.99% fidelity without ground-state cooling. https://arxiv.org/abs/2510.17286

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